Roller die



Aug. 28, 1951 w OFFUTT 2,565,780

ROLLER DIE Filed April 26, 1946 2 Sheets-Sheet 1 FIELl- 20 HIS ATTORNEY.

Filed April 26, 1946 2 Sheets-Sheet 2 FIG. 2.

HIS ATTORNEY.

Patented Aug. 28, 1951 ROLLER DIE John W. Offutt, Ellwood City, Pa., assignor to National Tube Company, a corporation of New Jersey Application April 26, 1946, Serial No. 665,168

2 "Claims.

This invention relates to metal reducing dies having cam-positioned rolls for effecting the desired reductions. Such dies are preferably used for reducing tubing telescoped over a supporting bar or mandrel.

It is an object of the present invention to produce light-Walled hot, or cold-rolled tubing.

It is a further object to produce tubing having a high D/T ratio.

The foregoing and further objects, together with the principles and method of operation of the invention, will be apparent from the following description and drawings, in which:

Figure l is a vertical longitudinal section of the die of my invention showing a tubular workpiece and mandrel disposed therein;

Figure 2 is an end elevation in the direction of the arrow and partly in section, showing the working pass;

Figure 3 is an enlarged detail of a portion of the pass; and

Figure 4 is an enlarged detail on line IV-IV of Figure 3.

Referring more particularly to the drawings, the numeral 2 designates a mandrel on which there is telescoped a tubular workpiece 4 disposed in the pass of the die 6 of my invention.

The die is composed of a circular housing l having a central opening l2 and a series of radially disposed longitudinally extending T-shaped tapered slots l4.

Small, trunnion-shaped, working rollers [6 having flat work-engaging faces l8, are disposed in segmental holders by cap screws 22.

The holders 20 are T-shaped in cross section so as to fit in the T-shaped slots 14. These holders have a channel 23 with oppositely disposed circular grooves 24 adjacent the outer edge throughout a large portion thereof to provide a guideway for the rollers, due to the trunnion-like extensions thereof being disposed in these grooves. On the inner side of the holder 20, that is, the side adjacent the pass, there are cams 26 having surfaces 28 which provide backing surfaces for the rolls IS. The surfaces 28 are parallel to the pass line and have curved ends 30 which are shaped to guide the rollers into and receive them from the guidewa formed by the grooves 24. The diameter of the rollers and the guideway provided by grooves 24 and cams 26 are proportioned so that the rollers substantially fill such space with a minimum of loss motion therebetween, so that the roller entering the work zone will follow the preceding roller rather 20 which are held together closely. Guides 32 are provided in the inner portions of the holders to hold the roller in position and alignment when there is no workpiece in the die. The" face of the rollers and cams is flat so that line contact therebetween may be maintained.

The holders 2B are secured and positioned within the housing It! by a split ring 34 mounted on the housing by bolts 36.

The housing Ill is mounted in a die holder on either a conventional draw or push bench after the rollers and holders are positioned and secured therein.

In operation, the bar or mandrel 2 with the tube 4 is pushed into the die until the workpiece engages the rollers at the entering end of the cams. As the rollers advance and squeeze the workpiece between the mandrel and the rollers, the wall of the tube is reduced and all rollers ahead and behind the rollers in contact with the work, are pushed alon their guideways so that one after another they come into working position.

Figure 4 indicates the action that takes place as the work progresses through the die. It will be noted on the entering end, the first roll moving over the curved end an of the cam 26 has just made contact with the workpiece 4 and that there is an unreduced section of tubing between the first and second roller, but that this section is reduced by the second roller as the tube progresses through the die. At the same time, the first roller is reducing its section. The backing up or straight surface 28 of the cam which is parallel to the axes of the bar and workpiece must belong enough to iron out any high spots left on the outside ofthe wo kpiece by the earlier action of the rollers. I 7

It should be noted that the workpiece will move along the bar as it elongates the wall reduction, with the result that the bar moves faster than the unreduced section of the workpiece. As shown in Figure 3, there is a side flow of metal between the rollers which acts to lift the sections of the workpiece between the adjacent rollers in such a way that the workpiece is somewhat loose on the bar, and thereby permits relative movement between the bar and the workpiece without excessive friction and resistance. This becomes of great importance when the workpiece is pushed through a series of dies as in such case there is a substantial longitudinal movement of the workpiece on the bar between and within the dies, which would not be possible if the tube were tight on the bar.

That is in hot drawing, the thin sections will be cooled more than the thick sections and therefore offer more resistance to deformation, andin 7 cold work the thin sections will be hardened throughout quicker than the thicker sections? reduce the sections between the rollers by a stretching action, one pass thronghthedieleaves substantially unreduced portions where not contacted by the rollers. This will in all cases necessitate the workpiece being simultaneously drawn 'zer .push'ed lthrougha-series of idles. As shown :by :adottedfilines in .Figure -3,, the successive dies should be disposed so that sthe'mid portion of '*;their rollers engage the ribsleft by the preceding mdie. I

The die of my inventionzhas zt'hepartieularly heneficial result :of requiring less power .for a given iamountxofrreduction than other ways of reducing annular sections-since the work rollers ,are rot-small. diameter-and accordingly the-arc of -;contact is small. ..-Moreover, since; the rolls travel with the-work;piece, sliding sfriction .is eliminated.

This die also has the advantagethatit can be reused on eitherv hot or .cold workpieces and lastly thinner-rolled :hot-rolled-tuhing -can .be produced than was -heretofore economically feasible.

. While .I have shown and described one specific embodiment .of my invention, it will be understand that this embodiment 'is merely for the ,purpose .ofillustra'tion-and description and that .various rotherforms may "be devised within the scope .of my invention, as 'definedinthe appended claims.

- lclaim:

' .1..A reducing 'die Tor'tubularmembers having an in'letand an outlet side, said die comprising 5a .cylindricalhcus'ingIhaving a concentric open- .ing therethrough, said "housing having a plu- :cality of equally spaced, longitudinally extending, T-shapedslots extending therethrough, said T-shaped slots vcomprisinghead and leg portions, the leg portions being radially disposed and the head portions transversely disposed of said housing, the legs of said slots opening into 'theinterrior Of said annular housing and being of decreasing length, the head portions thereof gradually converging toward the outlet side of said die, an annular ring .member mounted itransversely'of said die on the .outlet side thereof and extending into the concentric opening of said housing, T-shaped holding members comprising leg and head portions, said members being slidably disposed in said T-shaped slots, each of said holding members being interiorly grooved to form a roller guideway, a plurality v of rollers disposed in said roller guideways, back- .ingup cams disposed .betweensaidg-uideway a the inner faces 'of said holding members, the

backing-up cams of said holders combining to define an elongated substantially circular reducing pass, said T-shaped holders abutting said ring, and means for adjusting the position of said ring to var thesize of said reducin pass. While the lengthening of the tube tends to y g 2. A'reducing die for tubular members having an inlet and an 'outlet side, said die comprising :a *fcylindricalhousing having a concentric opening therethrough, said housing having a plurality of equally spaced, longitudinally extending, T-shaped slots extending therethrough, said i -shaped slotscomprising hread and leg porj'ti'ons, the leg portions being radially disposed and the "head portions transversely disposed of Isaid housing, the legs of said :slots opening into the interior of said annular housing and being of decreasing length,=the dread portions thereof gradually converging "toward the outlet side er -said die, .an .annular ring member mounted transversely of said die onithe outlet side thereof and extending into the concentric :opening of :said housing, 'T-shape'd, longitudinally split, 'hol'ding members "comprising leg and head portions, said members being slidably disposed in said T-shaped slotsyeach of r'saidrholding members being interiorly grooved to form a -C--shaped roller guideway, the ends of whichrextend to the "surface-of ntheinnerend of the leg portion, a plurrality :of rollers disposed *in .said .roller guideways, means extending inwardly .from said holders for guiding rsa'id rollers across the inner face of said holders, backing-up :cains disposed rhetween :said inwardly extending guiding .means and the inner faces of said holding members, the

backing-up cams of zsai'dholders combining to define .an elongated substant'ially'circular reducing pass, .said r-shaped .holders abutting said ring, and means for adjusting the position of said ring tovarythesize ofsaidreducing pass. JOHN W. OFFUTT.

REFERENCES CITED The following references are of record in-the Pfile of 'this patent:

UNI-IE1)STATES PATENTS 

